2017 OASDI Trustees Report

V. ASSUMPTIONS AND METHODS UNDERLYING
ACTUARIAL ESTIMATES

The future income and cost of the OASDI program will depend on many demographic, economic, and program-specific factors. Trust fund income will depend on how these factors affect the size and composition of the working population as well as the level and distribution of earnings. Similarly, program cost will depend on how these factors affect the size and composition of the beneficiary population as well as the general level of benefits.

The Trustees make basic assumptions for several of these factors based on analysis of historical trends, historical conditions, and expected future conditions. These factors include fertility, mortality, immigration, marriage, divorce, productivity, inflation, average earnings, unemployment, real interest rates, and disability incidence and termination. Other factors depend on these basic assumptions. These other, often interdependent, factors include total population, life expectancy, labor force participation, gross domestic product, and program-specific factors. Each year the Trustees reexamine these assumptions and methods in light of new information and make appropriate revisions. The assumptions for this report were established by the middle of January 2017, and have been accepted by the current members of the Board.

Future levels of these factors and their interrelationships are inherently uncertain. To address these uncertainties, this report uses three sets of assumptions, designated as intermediate (alternative II), low-cost (alternative I), and high-cost (alternative III). The intermediate set represents the Trustees’ best estimate of the future course of the population and the economy. With regard to the net effect on the actuarial status of the OASDI program, the low-cost set is more optimistic and the high-cost set is more pessimistic. The low-cost and high-cost sets of assumptions reflect significant potential changes in the interrelationships among factors, as well as changes in the values for individual factors.

While it is unlikely that all of the factors and interactions will differ in the specified directions from the intermediate values, many combinations of individual differences in the factors could have a similar overall effect. Outcomes with overall long-range cost as low as the low-cost scenario or as high as the high-cost scenario are very unlikely. This report also includes sensitivity analysis, where factors are changed one at a time (see appendix D), and a stochastic projection, which provides a probability distribution of possible future outcomes, with each input assumption centered around the intermediate alternative (see appendix E).

Readers should interpret with care the estimates based on the three sets of alternative assumptions. These estimates are not specific predictions of the future financial status of the OASDI program. Rather, they provide a reasonable range of future income and cost bounded by two plausible, albeit very unlikely, demographic and economic scenarios.

The Trustees assume that values for each of the demographic, economic, and program-specific factors change toward long-range ultimate values from recent levels or trends within the next 25 years. For extrapolations beyond the 75‑year long-range period, the ultimate levels or trends reached by the end of the 75‑year period remain unchanged. The assumed ultimate values represent average annual experience or growth rates. Actual future values will exhibit fluctuations or cyclical patterns, as in the past.

The following sections briefly discuss the various assumptions and methods required to make the estimates of trust fund financial status, which are the heart of this report.¹ There are, of course, many interrelationships among these factors that are important but are beyond the scope of this discussion.

A. DEMOGRAPHIC ASSUMPTIONS AND METHODS

This section of the report provides a brief overview of the demographic historical data and the assumptions used for the projections.

1. Fertility Assumptions

Birth rates by single year of age, for women aged 14 to 49,² are the basis for the fertility assumptions. These rates apply to the total number of women, across all marital statuses, in the midyear population at each age. Table V.A1 displays the historical and projected total fertility rates.³

Historically, birth rates in the United States have fluctuated widely. The total fertility rate decreased from 3.31 children per woman at the end of World War I (1918) to 2.15 during the Great Depression (1936). After 1936, the total fertility rate rose to 3.68 in 1957 and then fell to 1.74 by 1976. After 1976, the total fertility rate rose above 2.00 by 1990, where it generally remained through 2009, but dropped below 1.90 for 2011 through 2015. The recession and slow recovery in employment opportunity are likely contributing reasons for this recent low level.

These variations in the total fertility rate resulted from changes in many factors, including social attitudes, economic conditions, birth-control practices, and the racial/ethnic composition of the population. The Trustees expect future total fertility rates to remain relatively close to recent levels. Certain population characteristics, such as the higher percentages of women who have never married, of women who are divorced, and of young women who are in the labor force, are consistent with continued lower total fertility rates than those experienced during the baby-boom era (1946-65). Based on consideration of these factors, the Trustees assume ultimate total fertility rates of 2.20, 2.00, and 1.80 children per woman for the low-cost, intermediate, and high-cost assumptions, respectively. These ultimate rates are unchanged from last year’s report.

For the intermediate assumptions, the projected total fertility rate rises until it reaches 2.05 for 2023. This reflects the assumption that the drop in the total fertility rate below 2.0 children per woman during the recent economic downturn was in part a deferral in childbearing that will be partially offset with full economic recovery. Thereafter, the total fertility rate follows a linear trend toward the ultimate level in 2027. The assumed low-cost and high-cost total fertility rates trend away from the intermediate path and reach the ultimate values in 2024 and 2032, respectively.

2. Mortality Assumptions

For the projections in this year’s report, ultimate average annual percentage reductions in future mortality rates were assumed by age group and cause of death. These assumptions were then used to estimate future central death rates by age group, sex, and cause of death. From these estimated central death rates, probabilities of death by single year of age and sex were calculated.

Historical death rates are calculated for years 1900 through 2014 for ages below 65 (and for all ages for years prior to 1968) using data from the National Center for Health Statistics (NCHS).⁴ For ages 65 and over, final Medicare data on deaths and enrollments for years 1968 through 2013 and preliminary data for 2014 are used. Death rates by cause of death are produced for all ages for years 1979‑2014 using data from the NCHS.

The total age-sex-adjusted death rate⁵ declined at an average annual rate of 1.05 percent between 1900 and 2014. Between 1979 and 2014, the period for which death rates were analyzed by cause, the total age-sex-adjusted death rate, for all causes combined, declined at an average rate of 0.93 percent per year.

Death rates have declined substantially in the U.S. since 1900, with rapid declines over some periods and slow or no improvement over the other periods. Many factors are responsible for historical reductions in death rates, including medical advances, increased availability of health-care services, and improvements in sanitation and nutrition. Historical death rates generally declined more slowly for older ages and more rapidly for children and infants than for the rest of the population. Between 1900 and 2014, the age-sex-adjusted death rate for ages 65 and over declined at an average rate of 0.79 percent per year, while declining at an average rate of 3.07 percent per year for ages under 15.

Mortality assumptions differ for the low-cost, intermediate, and high-cost scenarios. Throughout the projection, the low-cost scenario contains annual percentage reductions that are smaller than those in the intermediate scenario, while those in the high-cost scenario are larger. The ultimate annual percentage reductions are the same as those in last year’s report.

The trends in the annual reductions in central death rates are calculated for the period from 2004 to 2014 by age group, sex, and cause of death. These trends are the starting reductions for alternative II. For alternatives I and III, 50 and 150 percent of the starting reductions are used, respectively. These annual reductions, by alternative, are assumed to transition rapidly from the starting reductions until they reach the ultimate annual percentage reductions assumed for 2041 and later.

Table V.A1 contains historical and projected age-sex-adjusted death rates for the total population (all ages), for ages under 65, and for ages 65 and over. Age-sex adjustment eliminates the effect of a changing distribution of population by age and sex, allowing the pure effects of changes in death rates to be observed. Under the intermediate assumptions, projected age-sex-adjusted death rates are, in general, slightly higher than the death rates in last year’s report for both the age group under 65 and the age group 65 and over. These changes primarily result from incorporating more recent historical data.

The projected average annual rate of decline for the total age-sex-adjusted death rate is about 0.42 percent, 0.77 percent, and 1.16 percent between 2016 and 2091 for alternatives I, II, and III, respectively. In keeping with the patterns observed in the historical data, the assumed future rates of decline are greater for younger ages than for older ages, but to a substantially lesser degree than in the past. Accordingly, the projected age-sex-adjusted death rates for ages 65 and over decline at average annual rates of about 0.37 percent, 0.68 percent, and 1.01 percent between 2016 and 2091 for alternatives I, II, and III, respectively. The projected age-sex-adjusted death rates for ages under 15 decline at average annual rates of about 0.81 percent, 1.60 percent, and 2.60 percent between 2016 and 2091 for alternatives I, II, and III, respectively.

Demographers express a wide range of views on the likely rate of future decline in death rates. For example, some believe that the long-standing historical tendency for mortality to decline more slowly at the highest ages will cease in the future. Others believe that biological factors, social factors, and limitations on health care spending may slow future rates of decline in mortality.⁶

The Trustees periodically revise the assumed ultimate rates of decline in mortality based on experience, new conditions, and expert opinion. Evolving trends in health care and lifestyle will determine what modifications to the assumed ultimate rates of decline in mortality will be warranted for future reports.

.

Table V.A1.—Fertility and Mortality Assumptions,^a
Calendar Years 1940-2095 

Calendar year		Total fertility rateb		Age-sex-adjusted death ratec per 100,000, by age
				Total	Under 65	65 and over
Historical data:
	1940	2.23		1,919.8	750.1	9,718.8
	1945	2.42		1,716.6	674.8	8,662.9
	1950	3.03		1,561.9	570.2	8,173.7
	1955	3.50		1,453.8	508.2	7,758.4
	1960	3.61		1,454.3	503.2	7,795.4
	1965	2.88		1,428.8	495.2	7,653.3
	1970	2.43		1,340.0	485.7	7,036.3
	1975	1.77		1,204.8	426.6	6,393.6
	1980	1.82		1,136.9	384.3	6,154.3
	1985	1.83		1,081.0	353.3	5,932.9
	1990	2.07		1,021.3	333.6	5,606.3
	1995	1.98		1,001.5	317.9	5,559.5
	2000	2.05		960.7	281.0	5,492.3
	2005	2.06		901.3	270.7	5,105.4
	2006	2.11		876.1	267.6	4,933.5
	2007	2.12		856.8	261.6	4,825.2
	2008	2.07		857.0	258.8	4,845.5
	2009	2.00		827.1	255.3	4,639.7
	2010	1.93		821.3	248.5	4,640.1
	2011	1.89		819.3	249.1	4,621.4
	2012	1.87		811.9	248.5	4,568.2
	2013	1.85		811.9	249.2	4,563.6
	2014	1.86		d805.4	251.1	d4,501.1
	2015	1.84		e787.9	e243.2	e4,419.6
	2016	e1.87		e779.8	e240.8	e4,373.7
Intermediate:
	2020	1.98		750.2	230.7	4,213.9
	2025	2.03		716.9	218.1	4,042.5
	2030	2.00		686.1	205.9	3,887.5
	2035	2.00		657.5	194.6	3,743.9
	2040	2.00		630.8	183.9	3,609.9
	2045	2.00		605.8	174.0	3,484.3
	2050	2.00		582.3	164.8	3,366.3
	2055	2.00		560.4	156.1	3,255.3
	2060	2.00		539.7	148.1	3,150.9
	2065	2.00		520.3	140.5	3,052.3
	2070	2.00		502.0	133.5	2,959.3
	2075	2.00		484.8	126.9	2,871.3
	2080	2.00		468.6	120.7	2,788.0
	2085	2.00		453.2	114.9	2,709.0
	2090	2.00		438.7	109.4	2,634.1
	2095	2.00		425.0	104.3	2,562.8
Low-cost:
	2020	2.07		779.0	239.7	4,374.5
	2025	2.20		762.6	233.4	4,290.8
	2030	2.20		745.9	226.8	4,207.1
	2035	2.20		729.6	220.4	4,125.1
	2040	2.20		713.8	214.1	4,045.4
	2045	2.20		698.4	208.0	3,968.2
	2050	2.20		683.6	202.2	3,893.6
	2055	2.20		669.3	196.5	3,821.4
	2060	2.20		655.4	191.1	3,751.5
	2065	2.20		642.0	185.8	3,683.8
	2070	2.20		629.1	180.7	3,618.3
	2075	2.20		616.5	175.8	3,554.8
	2080	2.20		604.4	171.1	3,493.3
	2085	2.20		592.6	166.5	3,433.7
	2090	2.20		581.2	162.1	3,375.8
	2095	2.20		570.2	157.8	3,319.8
High-cost:
	2020	1.90		719.4	220.7	4,044.1
	2025	1.89		667.6	201.0	3,778.7
	2030	1.83		622.2	183.0	3,550.8
	2035	1.80		581.9	166.9	3,348.7
	2040	1.80		545.7	152.5	3,167.1
	2045	1.80		513.1	139.7	3,003.0
	2050	1.80		483.7	128.2	2,853.8
	2055	1.80		457.0	117.9	2,717.7
	2060	1.80		432.7	108.6	2,593.2
	2065	1.80		410.5	100.3	2,478.7
	2070	1.80		390.2	92.7	2,373.3
	2075	1.80		371.5	85.9	2,275.7
	2080	1.80		354.3	79.7	2,185.3
	2085	1.80		338.4	74.1	2,101.1
	2090	1.80		323.7	68.9	2,022.6
	2095	1.80		310.1	64.2	1,949.2

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a

This table contains basic assumptions along with key summary values that are derived from basic assumptions.

b

The total fertility rate for any year is the average number of children that would be born to a woman in her lifetime if she were to experience, at each age of her life, the birth rate observed in, or assumed for, the selected year, and if she were to survive the entire childbearing period.

c

Based on the enumerated total population as of April 1, 2010, if that population were to experience the death rates by age and sex observed in, or assumed for, the selected year.

d

Estimated.

e

Estimated, intermediate alternative.

3. Immigration Assumptions

Projections of the total Social Security area population reflect assumptions for annual legal immigration, legal emigration, “other immigration,” and “other emigration.” Legal immigration consists of persons who are granted legal permanent resident status. Legal emigration consists of legal permanent residents and citizens who leave the Social Security area population. Net legal immigration is the difference between legal immigration and legal emigration. “Other immigration” consists of immigrants who enter the Social Security area in a given year and stay to the end of that year without having legal permanent resident status, such as undocumented immigrants and temporary foreign workers and students. “Other emigration” consists of other immigrants who leave the Social Security area population or who adjust their status to become legal permanent residents. Net other immigration is the difference between other immigration and other emigration. Net immigration refers to the sum of net legal immigration and net other immigration.

Immigration assumptions differ for the low-cost, intermediate, and high-cost scenarios. The low-cost scenario includes higher annual net immigration and the high-cost scenario includes lower annual net immigration. Table V.A2 contains historical and projected levels of various immigration flows.

Legal immigration has increased significantly since World War II, due to various events and legislative changes, including the Immigration Act of 1965 and the Immigration Act of 1990.

The intermediate alternative assumes that annual legal immigration, including those who adjust their status to become legal permanent residents, will be 1,060,000 persons for 2016 and later. Alternatives I and III assume that ultimate annual legal immigration will be 1,260,000 persons and 860,000 persons, respectively, for 2017 and later. The ultimate levels of legal immigration are unchanged from last year’s report.

The assumed ratios of annual legal emigration to legal immigration are 20, 25, and 30 percent for alternatives I, II, and III, respectively. This range is consistent with the limited historical data for legal emigration from the Social Security area. These ratios are unchanged from last year’s report. Under the intermediate alternative, by combining the ultimate annual legal immigration and emigration assumptions, ultimate annual net legal immigration is 795,000 persons. For the low-cost and high-cost scenarios, ultimate annual net legal immigration is about 1,008,000 persons and 602,000 persons, respectively.

The estimated number of other immigrants residing in the Social Security area and the annual level of other immigration have been affected significantly by the recent recession. Net other immigration was greatly reduced during the economic downturn. Under the intermediate assumptions, annual other immigration is expected to increase from recent levels, reflecting a continued recovery from levels experienced during the recession. The ultimate levels of other immigration are unchanged from last year’s report: 1,350,000 persons for alternative II, 1,650,000 persons for alternative I, and 1,050,000 persons for alternative III.

Emigration from the other-immigrant population includes those who leave the Social Security area and those who adjust their status to become legal permanent residents. This other-immigrant population is highly mobile and far more likely to leave the Social Security area than is the citizen or legal permanent resident population. As individuals from this population reside in the country for extended periods of time, they generally become less likely to leave the country.

Under the intermediate assumptions, the total annual number of other emigrants who leave the Social Security area averages about 418,000 through the 75‑year projection period. In addition, the ultimate annual number of other immigrants who adjust status to become legal permanent residents is assumed to be 450,000 for the intermediate assumptions. This is one-third of the assumed ultimate annual number of other immigrants entering the Social Security area. For the low-cost and high-cost scenarios, the total annual number of other emigrants averages about 495,000 and 327,000, respectively, through the 75‑year projection period. The ultimate annual number of people adjusting status to legal permanent resident status is assumed to be 550,000 persons and 350,000 persons, for the low-cost and high-cost scenarios, respectively. The ultimate annual number of people adjusting status to become legal permanent residents is unchanged from last year’s report.

Under the assumptions and methods described above, the projected size of the other-immigrant population grows substantially. This growth reflects the excess of annual other immigration over the combined annual numbers of emigrants and deaths that occur within the other-immigrant population.

Under the intermediate assumptions, projected net other immigration reaches a peak in 2018, reflecting the recovering economy, then sharply decreases over the next few years, primarily due to the decline in the number of other immigrants entering the country, to a stable long-term level. This is followed by a gradual decrease in net other immigration after 2022, due to the increasing number of other immigrants residing in the Social Security area. Because the number of other immigrants leaving the Social Security area is based on rates of departure, an increase in the number of other immigrants residing in the Social Security area results in an increase in the number who emigrate out of the area. All other components of other immigration and emigration are assumed to be stable after 2022, and thus do not contribute toward any change in net other immigration. Under the intermediate assumptions, the projected average annual level of net other immigration over the 75-year projection period is about 491,000 persons. For the low-cost and high-cost assumptions, projected average annual net other immigration is about 615,000 persons and 359,000 persons, respectively.

The projected average total level of net immigration (legal and other, combined) is about 1,286,000 persons per year during the 75-year projection period under the intermediate assumptions. For the low-cost and high-cost assumptions, projected average annual total net immigration is about 1,623,000 persons and 961,000 persons, respectively.

Demographers express a wide range of views about the future course of immigration for the United States. Some believe that net immigration will increase substantially in the future. Others believe that potential immigrants may be increasingly attracted to other countries, that the number of potential immigrants may be lower due to lower birth rates in many countries, or that changes in the law or enforcement of the law could reduce immigration. The average of the 2015 Technical Panel’s recommended annual levels of total net immigration for the 75-year projection period is very close to the average projected in this year’s report.

Table V.A2.—Immigration Assumptions,^a Calendar Years 1940-2095 

[in thousands]

Calendar year		Legal immigration					Other-than-legal immigrationb				Total net immigration
		Legal in	Legal out	Adjustments of statusc d	Net legal		Other in	Other out	Adjustments of statusc d	Net other
Historical data:
	1940	-	-	-	46		-	-	-	-	-
	1945	73	18	-	55		-	-	-	-	-
	1950	227	57	-	171		-	-	-	-	-
	1955	280	70	-	210		-	-	-	-	-
	1960	268	67	-	201		-	-	-	-	-
	1965	261	77	49	232		-	-	49	-	-
	1970	307	93	65	279		-	-	65	-	-
	1975	340	98	53	294		-	-	53	-	-
	1980	431	136	112	407		-	-	112	208	614
	1985	458	144	119	432		-	-	119	264	696
	1990	548	166	114	497		-	-	114	620	1,116
	1995	511	192	255	575		-	-	255	557	1,132
	2000	482	224	413	672		1,409	294	413	703	1,374
	2005	561	290	597	869		1,773	35	597	1,141	2,010
	2006	639	303	573	909		1,428	54	573	800	1,709
	2007	584	267	482	800		926	373	482	71	871
	2008	635	278	478	835		707	985	478	-755	79
	2009	633	277	475	832		800	221	475	104	935
	2010	622	262	426	786		683	208	426	50	835
	2011	647	264	408	791		609	270	408	-69	722
	2012	621	255	401	766		694	701	401	-407	359
	2013	589	249	409	748		820	500	409	-88	660
	2014	627	256	398	769		1,063	353	398	311	1,080
	2015 5	661	263	390	788		1,200	173	390	637	1,425
	2016 6	610	265	450	795		1,450	198	450	802	1,597
Intermediate:
	2020	610	265	450	795		1,450	283	450	717	1,512
	2025	610	265	450	795		1,350	332	450	568	1,363
	2030	610	265	450	795		1,350	363	450	537	1,332
	2035	610	265	450	795		1,350	390	450	510	1,305
	2040	610	265	450	795		1,350	413	450	487	1,282
	2045	610	265	450	795		1,350	428	450	472	1,267
	2050	610	265	450	795		1,350	438	450	462	1,257
	2055	610	265	450	795		1,350	446	450	454	1,249
	2060	610	265	450	795		1,350	452	450	448	1,243
	2065	610	265	450	795		1,350	457	450	443	1,238
	2070	610	265	450	795		1,350	461	450	439	1,234
	2075	610	265	450	795		1,350	464	450	436	1,231
	2080	610	265	450	795		1,350	466	450	434	1,229
	2085	610	265	450	795		1,350	467	450	433	1,228
	2090	610	265	450	795		1,350	468	450	432	1,227
	2095	610	265	450	795		1,350	469	450	431	1,226
Low-cost:
	2020	710	252	550	1,008		1,750	304	550	896	1,904
	2025	710	252	550	1,008		1,650	369	550	731	1,739
	2030	710	252	550	1,008		1,650	412	550	688	1,696
	2035	710	252	550	1,008		1,650	451	550	649	1,657
	2040	710	252	550	1,008		1,650	483	550	617	1,625
	2045	710	252	550	1,008		1,650	506	550	594	1,602
	2050	710	252	550	1,008		1,650	522	550	578	1,586
	2055	710	252	550	1,008		1,650	535	550	565	1,573
	2060	710	252	550	1,008		1,650	544	550	556	1,564
	2065	710	252	550	1,008		1,650	552	550	548	1,556
	2070	710	252	550	1,008		1,650	557	550	543	1,551
	2075	710	252	550	1,008		1,650	561	550	539	1,547
	2080	710	252	550	1,008		1,650	564	550	536	1,544
	2085	710	252	550	1,008		1,650	565	550	535	1,543
	2090	710	252	550	1,008		1,650	566	550	534	1,542
	2095	710	252	550	1,008		1,650	567	550	533	1,541
High-cost:
	2020	510	258	350	602		850	226	350	274	876
	2025	510	258	350	602		1,050	257	350	443	1,045
	2030	510	258	350	602		1,050	281	350	419	1,021
	2035	510	258	350	602		1,050	302	350	398	1,000
	2040	510	258	350	602		1,050	319	350	381	983
	2045	510	258	350	602		1,050	331	350	369	971
	2050	510	258	350	602		1,050	340	350	360	962
	2055	510	258	350	602		1,050	347	350	353	955
	2060	510	258	350	602		1,050	352	350	348	950
	2065	510	258	350	602		1,050	356	350	344	946
	2070	510	258	350	602		1,050	360	350	340	942
	2075	510	258	350	602		1,050	362	350	338	940
	2080	510	258	350	602		1,050	364	350	336	938
	2085	510	258	350	602		1,050	366	350	334	936
	2090	510	258	350	602		1,050	367	350	333	935
	2095	510	258	350	602		1,050	368	350	332	934

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a

This table contains basic assumptions along with key summary values that are derived from basic assumptions.

b

Historical other immigration and emigration estimates depend on a residual method, using Department of Homeland Security (DHS) January 1 stock estimates for 2005 through 2012, and internally developed January 1 stock estimates based on DHS methods for 2013 through 2015.

c

Estimates do not include persons who attained legal permanent resident status under the special one-time provisions of the Immigration Reform and Control Act of 1986.

d

Adjustments of status are a positive for net legal immigration and a negative for net other immigration.

e

Estimated.

f

Estimated, intermediate alternative.

Note: Totals do not necessarily equal the sums of rounded components.

4. Total Population Estimates

The starting Social Security area population for December 31, 2014, is derived from the Census Bureau’s estimate of the residents of the 50 States and D.C. and U.S. Armed Forces overseas. Adjustments are made to reflect mortality assumptions for the aged population since 2010 that are consistent with Medicare and Social Security data, net immigration assumptions for the aged population since 2010, estimates of the net undercount in the 2010 census, inclusion of U.S. citizens living abroad (including residents of U.S. territories), and inclusion of non-citizens living abroad who are insured for Social Security benefits. The Office of the Chief Actuary projects the population in the Social Security area by age, sex, and marital status for December 31 of each year from 2015 through 2095 by combining the assumptions for future fertility, mortality, and immigration with assumptions for marriage and divorce. Previous sections of this chapter present the assumptions for future fertility, mortality, and immigration. Assumptions for future rates of marriage and divorce reflect historical data from the National Center for Health Statistics, the Census Bureau, and selected individual States.

This report presents a July 1 (i.e., midyear) population for each year, which is derived from surrounding December populations. Table V.A3 shows the historical and projected population for July 1 by broad age group, for the three alternatives. It also shows the aged and total dependency ratios (see table footnotes for definitions).

Table V.A3.—Social Security Area Population on July 1 and Dependency Ratios, Calendar Years 1945-2095 

Calendar year		Population (in thousands)					Dependency ratio
		Under 20	20-64	65 and over	Total		Ageda	Totalb
Historical data:
	1945	49,121	88,109	10,900	148,130		0.124	0.681
	1950	53,903	92,382	12,769	159,053		.138	.722
	1955	63,293	96,207	15,075	174,576		.157	.815
	1960	73,074	99,802	17,277	190,153		.173	.905
	1965	80,020	104,885	19,071	203,975		.182	.945
	1970	81,020	112,991	20,895	214,906		.185	.902
	1975	78,629	122,642	23,307	224,578		.190	.831
	1980	74,835	134,106	26,309	235,250		.196	.754
	1985	72,948	144,577	29,151	246,676		.202	.706
	1990	74,797	152,768	31,925	259,491		.209	.699
	1995	79,278	160,729	34,318	274,325		.214	.707
	2000	82,003	170,181	35,503	287,687		.209	.690
	2005	83,979	181,065	37,158	302,202		.205	.669
	2006	84,568	183,340	37,724	305,632		.206	.667
	2007	85,147	184,970	38,479	308,596		.208	.668
	2008	85,542	185,797	39,366	310,704		.212	.672
	2009	85,766	186,734	40,246	312,746		.216	.675
	2010	85,723	188,418	41,039	315,180		.218	.673
	2011	85,451	190,046	42,009	317,507		.221	.671
	2012	85,159	190,989	43,401	319,549		.227	.673
	2013	84,915	191,737	44,876	321,528		.234	.677
	2014	84,838	192,744	46,283	323,866		.240	.680
	2015c	84,910	193,852	47,738	326,499		.246	.684
	2016  c	85,131	194,917	49,264	329,312		.253	.690
Intermediate:
	2020	86,917	198,586	56,060	341,562		.282	.720
	2025	89,962	201,594	65,315	356,870		.324	.770
	2030	92,330	205,002	73,459	370,791		.358	.809
	2035	96,076	208,655	78,510	383,242		.376	.837
	2040	98,786	214,092	81,342	394,219		.380	.841
	2045	99,854	220,951	83,359	404,164		.377	.829
	2050	101,366	226,580	85,920	413,865		.379	.827
	2055	103,569	231,311	89,200	424,080		.386	.833
	2060	106,251	235,374	93,298	434,924		.396	.848
	2065	108,959	240,053	97,080	446,092		.404	.858
	2070	111,318	244,798	101,117	457,233		.413	.868
	2075	113,224	249,690	105,285	468,200		.422	.875
	2080	115,033	256,379	107,632	479,044		.420	.869
	2085	117,135	262,269	110,566	489,970		.422	.868
	2090	119,533	266,576	114,955	501,063		.431	.880
	2095	121,974	271,092	119,186	512,251		.440	.890
Low-cost:
	2020	88,020	199,768	55,889	343,677		0.280	0.720
	2025	93,238	204,078	64,788	362,104		.317	.774
	2030	98,632	208,796	72,411	379,839		.347	.819
	2035	105,520	213,740	76,820	396,080		.359	.853
	2040	110,974	220,930	78,965	410,868		.357	.860
	2045	113,996	230,597	80,356	424,949		.348	.843
	2050	117,212	239,853	82,428	439,493		.344	.832
	2055	121,818	248,242	85,386	455,446		.344	.835
	2060	127,518	255,983	89,275	472,776		.349	.847
	2065	133,388	264,579	92,870	490,837		.351	.855
	2070	138,630	273,850	96,652	509,131		.353	.859
	2075	143,079	284,085	100,474	527,639		.354	.857
	2080	147,391	296,774	102,484	546,649		.345	.842
	2085	152,310	308,650	105,516	566,476		.342	.835
	2090	157,899	318,302	110,934	587,135		.349	.845
	2095	163,669	327,822	116,902	608,393		.357	.856
High-cost:
	2020	85,228	196,326	56,226	337,780		.286	.721
	2025	86,192	197,881	65,869	349,942		.333	.768
	2030	86,209	200,096	74,599	360,903		.373	.804
	2035	87,045	202,596	80,375	370,016		.397	.826
	2040	87,279	206,379	83,979	377,637		.407	.830
	2045	86,667	210,607	86,694	383,968		.412	.823
	2050	86,415	213,296	89,779	389,489		.421	.826
	2055	86,797	214,647	93,350	394,794		.435	.839
	2060	87,226	215,312	97,561	400,099		.453	.858
	2065	87,536	216,399	101,409	405,343		.469	.873
	2070	87,658	217,076	105,583	410,317		.486	.890
	2075	87,608	217,257	109,997	414,861		.506	.910
	2080	87,578	218,718	112,598	418,894		.515	.915
	2085	87,736	219,522	115,260	422,518		.525	.925
	2090	88,022	219,429	118,386	425,837		.540	.941
	2095	88,277	219,583	121,011	428,872		.551	.953

---

a

Ratio of the population at ages 65 and over to the population at ages 20-64.

b

Ratio of the population at ages 65 and over and the population under age 20 to the population at ages 20‑64.

c

Estimated, intermediate alternative.

Notes:
1. Historical data are subject to revision.
2. Totals do not necessarily equal the sums of rounded components.

5. Life Expectancy Estimates

Life expectancy, or the average remaining number of years expected prior to death, is an additional way to summarize the Trustees’ mortality assumptions. This report includes life expectancy in two different forms (period and cohort) for two separate purposes.

•

Period life expectancy for a given year uses the actual or expected death rates at each age for that year. It is a useful summary statistic for illustrating the overall level of the death rates experienced in a single year. Period life expectancy for a particular year provides an individual’s expected average remaining lifetime at a selected age, assuming no change in death rates after that year. Table V.A4 presents historical and projected life expectancy calculated on a period basis.

•

Cohort life expectancy does not use death rates for a single year, but for the series of years in which the individual will actually reach each succeeding age if he or she survives. Cohort life expectancy provides an individual’s expected average remaining lifetime at a selected age in a given year, using actual or expected future changes in death rates. Table V.A5 presents historical and projected life expectancy calculated on a cohort basis. Cohort life expectancy is somewhat greater than period life expectancy for a given year because: (1) death rates at any age tend to decline over time; and (2) cohort life expectancy uses death rates from future years, while period life expectancy uses death rates only from the given year.

Life expectancy at a given age reflects death rates at that and all older ages. Period life expectancy is somewhat related to the age-sex-adjusted death rate discussed in section V.A.2. However, life expectancy places far greater weight on death rates at lower ages than at higher ages. Therefore, changes in death rates at lower ages have far greater effects in changing life expectancy over time. It is important to keep this concept in mind when considering trends in life expectancy.

Table V.A4.—Period Life Expectancy^a

		Historical data
Calendar year		At birth			At age 65
		Male	Female		Male	Female
	1940	61.4	65.7		11.9	13.4
	1945	62.9	68.4		12.6	14.4
	1950	65.6	71.1		12.8	15.1
	1955	66.7	72.8		13.1	15.6
	1960	66.7	73.2		12.9	15.9
	1965	66.8	73.8		12.9	16.3
	1970	67.2	74.9		13.1	17.1
	1975	68.7	76.6		13.7	18.0
	1980	69.9	77.5		14.0	18.4
	1985	71.1	78.2		14.4	18.6
	1990	71.8	78.9		15.1	19.1
	1995	72.5	79.1		15.4	19.1
	2000	74.0	79.4		15.9	19.0
	2005	74.8	80.0		16.7	19.5
	2006	75.1	80.2		17.0	19.7
	2007	75.4	80.5		17.2	19.9
	2008	75.5	80.5		17.2	19.9
	2009	75.9	80.8		17.5	20.2
	2010	76.1	80.9		17.6	20.2
	2011	76.2	81.0		17.7	20.2
	2012	76.3	81.0		17.8	20.3
	2013	76.3	81.1		17.8	20.3
	2014b	76.3	81.1		17.8	20.4
	2015c	76.7	81.4		18.1	20.6
	2016  c	76.9	81.5		18.2	20.7
		Intermediate						Low-cost						High-cost
Calendar year		At birth			At age 65			At birth			At age 65			At birth			At age 65
		Male	Female		Male	Female		Male	Female		Male	Female		Male	Female		Male	Female
	2020	77.4	81.9		18.5	20.9		76.9	81.5		18.2	20.7		77.9	82.3		18.9	21.2
	2025	78.0	82.4		18.9	21.3		77.2	81.7		18.4	20.8		78.9	83.1		19.5	21.8
	2030	78.6	82.9		19.2	21.6		77.5	82.0		18.6	21.0		79.9	83.9		20.0	22.2
	2035	79.2	83.3		19.6	21.8		77.8	82.2		18.7	21.1		80.7	84.6		20.5	22.7
	2040	79.7	83.8		19.9	22.1		78.1	82.5		18.9	21.3		81.5	85.3		21.0	23.1
	2045	80.2	84.2		20.2	22.4		78.4	82.7		19.1	21.4		82.3	85.9		21.4	23.5
	2050	80.7	84.6		20.5	22.7		78.7	83.0		19.2	21.6		83.0	86.5		21.9	23.9
	2055	81.2	85.0		20.7	22.9		79.0	83.2		19.4	21.7		83.6	87.0		22.3	24.3
	2060	81.7	85.4		21.0	23.2		79.2	83.4		19.6	21.8		84.3	87.5		22.7	24.6
	2065	82.1	85.8		21.3	23.4		79.5	83.6		19.7	22.0		84.9	88.0		23.0	25.0
	2070	82.5	86.1		21.6	23.6		79.8	83.8		19.9	22.1		85.4	88.5		23.4	25.3
	2075	83.0	86.5		21.8	23.9		80.0	84.1		20.0	22.3		86.0	88.9		23.8	25.6
	2080	83.4	86.8		22.1	24.1		80.3	84.3		20.2	22.4		86.5	89.4		24.1	26.0
	2085	83.7	87.1		22.3	24.3		80.5	84.5		20.3	22.5		87.0	89.8		24.4	26.3
	2090	84.1	87.4		22.5	24.5		80.8	84.7		20.4	22.7		87.4	90.2		24.7	26.6
	2095	84.5	87.7		22.8	24.7		81.0	84.9		20.6	22.8		87.9	90.5		25.1	26.8

---

a

The period life expectancy at a given age for a given year is the average remaining number of years expected prior to death for a person at that exact age, born on January 1, using the mortality rates for that year over the course of his or her remaining life.

b

Estimated.

c

Estimated, intermediate alternative.

Table V.A5.—Cohort Life Expectancy^a

Calendar year	Intermediate						Low-cost						High-cost
	At birthb			At age 65c			At birthb			At age 65c			At birthb			At age 65  c
	Male	Female		Male	Female		Male	Female		Male	Female		Male	Female		Male	Female
1940	70.4	76.6		12.7	14.7		70.3	76.4		12.7	14.7		70.6	76.9		12.7	14.7
1945	72.3	78.3		13.0	15.4		72.0	78.0		13.0	15.4		72.6	78.8		13.0	15.4
1950	73.5	79.7		13.1	16.2		73.0	79.2		13.1	16.2		74.0	80.2		13.1	16.2
1955	74.1	80.2		13.1	16.7		73.5	79.6		13.1	16.7		74.8	81.0		13.1	16.7
1960	74.8	80.7		13.2	17.4		74.0	79.9		13.2	17.4		75.8	81.6		13.2	17.4
1965	75.8	81.2		13.5	18.0		74.8	80.3		13.5	18.0		77.0	82.4		13.5	18.0
1970	77.0	82.1		13.8	18.5		75.8	80.9		13.8	18.5		78.4	83.5		13.8	18.5
1975	77.9	82.8		14.2	18.7		76.5	81.5		14.2	18.7		79.6	84.4		14.2	18.7
1980	78.8	83.5		14.7	18.8		77.2	82.0		14.7	18.8		80.7	85.3		14.7	18.8
1985	79.5	84.1		15.4	19.1		77.7	82.4		15.4	19.1		81.7	86.0		15.4	19.1
1990	80.2	84.6		16.1	19.4		78.2	82.8		16.1	19.4		82.6	86.7		16.1	19.5
1995	81.0	85.2		16.8	19.8		78.7	83.1		16.7	19.7		83.6	87.4		16.8	19.9
2000	81.5	85.6		17.5	20.2		79.1	83.4		17.4	20.1		84.3	88.0		17.7	20.4
2005	82.0	86.0		18.2	20.7		79.4	83.7		17.9	20.5		84.9	88.5		18.4	21.1
2006	82.1	86.0		18.3	20.8		79.4	83.7		18.0	20.5		85.1	88.6		18.6	21.2
2007	82.2	86.1		18.4	20.9		79.5	83.8		18.1	20.6		85.2	88.7		18.7	21.3
2008	82.3	86.2		18.4	21.0		79.5	83.8		18.1	20.6		85.3	88.8		18.8	21.4
2009	82.4	86.3		18.5	21.1		79.6	83.9		18.2	20.7		85.5	88.9		19.0	21.5
2010	82.5	86.4		18.6	21.1		79.7	83.9		18.2	20.7		85.6	89.1		19.1	21.6
2011	82.6	86.4		18.7	21.2		79.7	84.0		18.3	20.8		85.7	89.1		19.2	21.7
2012	82.7	86.5		18.8	21.3		79.8	84.0		18.3	20.8		85.9	89.2		19.3	21.9
2013	82.8	86.6		18.9	21.4		79.9	84.1		18.4	20.8		86.0	89.3		19.5	22.0
2014	82.9	86.7		18.9	21.4		79.9	84.1		18.4	20.9		86.1	89.4		19.6	22.1
2015	83.0	86.7		19.0	21.5		80.0	84.2		18.5	20.9		86.2	89.5		19.7	22.2
2016	83.1	86.8		19.1	21.6		80.0	84.2		18.5	21.0		86.4	89.7		19.8	22.3
2020	83.4	87.1		19.4	21.8		80.2	84.4		18.6	21.1		86.8	90.0		20.3	22.7
2025	83.9	87.5		19.7	22.1		80.5	84.6		18.8	21.2		87.4	90.5		20.8	23.2
2030	84.3	87.8		20.0	22.4		80.8	84.8		19.0	21.4		87.9	90.9		21.3	23.6
2035	84.7	88.1		20.4	22.7		81.0	85.0		19.2	21.5		88.5	91.4		21.8	24.0
2040	85.0	88.4		20.7	22.9		81.3	85.2		19.3	21.7		88.9	91.8		22.3	24.4
2045	85.4	88.7		21.0	23.2		81.5	85.4		19.5	21.8		89.4	92.1		22.7	24.8
2050	85.8	89.0		21.2	23.5		81.7	85.6		19.6	22.0		89.9	92.5		23.1	25.2
2055	86.1	89.3		21.5	23.7		82.0	85.8		19.8	22.1		90.3	92.9		23.5	25.5
2060	86.4	89.6		21.8	23.9		82.2	86.0		20.0	22.3		90.7	93.2		23.9	25.9
2065	86.8	89.8		22.0	24.2		82.4	86.2		20.1	22.4		91.1	93.5		24.2	26.2
2070	87.1	90.1		22.3	24.4		82.6	86.3		20.3	22.5		91.5	93.8		24.6	26.5
2075	87.4	90.3		22.5	24.6		82.8	86.5		20.4	22.7		91.8	94.2		24.9	26.8
2080	87.7	90.6		22.8	24.8		83.1	86.7		20.5	22.8		92.2	94.4		25.2	27.1
2085	88.0	90.8		23.0	25.1		83.3	86.9		20.7	22.9		92.5	94.7		25.6	27.4
2090	88.2	91.1		23.2	25.3		83.5	87.0		20.8	23.1		92.9	95.0		25.9	27.7
2095	88.5	91.3		23.5	25.5		83.7	87.2		21.0	23.2		93.2	95.3		26.2	28.0

---

a

The cohort life expectancy at a given age for a given year is the average remaining number of years expected prior to death for a person at that exact age, born on January 1, using the mortality rates for the series of years in which the individual will actually reach each succeeding age if he or she survives.

b

Cohort life expectancy at birth for those born in the calendar year is based on a combination of actual, estimated, and projected death rates for birth years 1940 through 2014. For birth years after 2014, these values depend on estimated and projected death rates.

c

Age 65 cohort life expectancy for those attaining age 65 in calendar years 1940 though 2013 depends on actual death rates or on a combination of actual, estimated, and projected death rates. After 2013, these values depend on estimated and projected death rates.

---

1

Actuarial Studies published by the Office of the Chief Actuary, Social Security Administration, contain further details about the assumptions, methods, and actuarial estimates. A complete list of available studies may be found at www.ssa.gov/OACT/NOTES/actstud.html. To obtain copies of such studies or of this report, please submit a request at www.ssa.gov/OACT/request.html or write to: Office of the Chief Actuary, 700 Altmeyer Building, 6401 Security Boulevard, Baltimore, MD 21235. This entire report, along with supplemental year-by-year tables and additional documentation on assumptions and methods, may be found at www.ssa.gov/OACT/TR/2017/.

2

Birth rates at age 14 include births to women aged 14 and under, and birth rates at age 49 include births to women aged 49 and over.

3

The total fertility rate may be interpreted as the average number of children that would be born to a woman in her lifetime if she were to experience, at each age of her life, the birth rate observed in, or assumed for, a specified year, and if she were to survive the entire childbearing period. A rate of about 2.1 would ultimately result in a nearly constant population if immigration and emigration were both zero, and if death rates were to remain at current levels.

4

These rates reflect NCHS data on deaths and Census estimates of population.

5

Based on the enumerated total population as of April 1, 2010, if that population were to experience the death rates by age and sex for the selected year.

6

The 2015 Technical Panel on Assumptions and Methods, appointed by the Social Security Advisory Board, recommended retaining ultimate rates of improvement that vary by age and cause of death as assumed by the Trustees, but with an overall rate of improvement on an age-sex-adjusted basis of 1.00 percent.